Shells, features and interaction
Doug Gwyn <gwyn>
gwyn at brl-tgr.ARPA
Thu Dec 5 17:28:54 AEST 1985
Oh boy! Shell wars!
> The System V implementation of functions has the following deficiencies
> most of which exist in the 8th. edition Bourne shell:
Well, Dave, I always thought you were the one who added this feature
to the System V shell for Release 2.0; guess I was mistaken. Whoever
did it, it would be interesting to hear why the particular design was
arrived at and whether it will be improved in future releases.
> For the sake of simplicity, the Bourne shell is riddled with little things
> that confuse the user. Consider the following list of annoyances of the
> 'simple' Bourne shell:
> 2. sh script doesn't perform path search for script.
Why should it? I would be very upset if it did, since my cwd is last
in my $PATH for good and sufficient reasons, and I often am testing
new versions of scripts that live in public places.
> 8. PATH=/bin:/usr/bin: will not search current directory last.
That's simply a bug. I posted a fix for this some time ago.
(The fixed version is even simpler and smaller.)
> 14. | and ^ are used as synonyms.
That was for compatibility, to avoid breaking old shell scripts.
I admit that at this point in time it is more just a nuisance.
The SVR2 shell is on the verge of becoming too big for 64Kb address
space machines such as the PDP-11. Some of us think it would be a
shame for UNIX to be unimplementable on small systems due to the
shell being too big. Perhaps a subset/superset approach (like sh/ksh)
would be best.
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